Default Current Test Method of Impulse Voltage Mixed High Voltage Direct Current Converter Valve

ABSTRACT

The test method of this invention is comparatively simpler without high voltages in normal default current tests, high voltages have been replaced by impulse generator employing positive and negative symmetrical voltages mixed with impulse voltages to form asymmetrical forward and reverse high voltages, meanwhile the timing for impulse voltage is flexible, the amplitudes could be continuously adjustable according to specific needs, to make test voltage exactly reach climax upon certain timing, the test is flexible and safe, to be applied to converter valves in different direct currents.

TECHNICAL FIELD

This invention relates to one test method of direct current converter valve, specifically relates to one test method of impulse voltage mixed high voltage direct current converter valve.

BACKGROUND

As progress and wide spreading of high voltage direct current transferring in electrical system, the reliability of core unit-huge power high voltage series connecting thyristor valve becomes the key to system safety. Furthermore default current test relates to the level of design and manufacturing of high voltage series connecting thyristor valve, and is very important a test measure to improve its reliability, to testify the hugest current, voltage and temperature stress design due to short circuit which could born by converter valve are correct. Nowadays the mixture test idea has been widely used to test default current of direct current converter valve. Its basic idea is to employ direct current supply, default current supply, high voltage supply etc. multiple sets of power supply systems respectively charging heating current, default current and forward, reverse high voltages after default. Mixed test loop could achieve following two tests.

a) following up blocking single wave default current test—suppress one maximum amplitude of single wave default current, beginning from highest temperature, reverse and forward voltages following blocking, including any over voltage due to load rejection;

b) non-following up blocking multiple wave default current test—with the same condition of single wave, until breaker trips, multiple default current still exist, without forward voltage.

At present high voltage supply in test circuit generally consists of L, C oscillation circuit, its positive and negative high voltages are symmetrical. Therefore during single wave default current test, generally mixed test loop after default current dies, provides the same amplitudes of forward and reverse high voltages. In practice, after test valve goes through default current, converter valve first goes through reverse voltage, then voltage rises to positive climax and the amplitude of hugest reverse voltage should be less than that of forward voltage, meanwhile the temperature of test valve gradually goes down. General mixed test loop providing over reverse voltage is very adverse to high temperature converter valve which has just been gone through default current and has the potential to damage test valve. In addition, in practice, the timing for climax of forward voltage upon converter valve is 5 ms behind that of its reverse voltage, in general mixed test loop, to achieve this requirement relevant circuit parameters must be modified, which adds to more cost and inconvenience of test.

INVENTION

This invention provides one default current test method of impulse voltage mixed high voltage direct current converter valve, employing positive and negative symmetrical voltages mixed with impulse voltages to form asymmetrical forward and reverse high voltages, meanwhile the timing for impulse voltage is flexible, the amplitudes could be continuously adjustable according to specific needs, to make test voltage exactly reach climax upon certain timing, the test is flexible and safe, to be applied to converter valves in different direct currents.

This invention provides one default current test method of impulse voltage mixed high voltage direct current converter valve, the apparatuses in said method comprises test valve 1, direct current supply 2, auxiliary valve 3, default current supply 4, its improvements are, the apparatuses in said method comprises impulse generator 5; the said impulse generator 5 series connects auxiliary valve 3 after parallel connecting test valve 1; the said test valve 1 series connecting auxiliary valve 3 to form bridge of 6 pulse bridge rectifier B6; the inductance L of said default current supply 4 parallel connects impulse generator 5.

In one of preferred embodiment of this invention, the default current supply 4 of test apparatuses comprise direct current supply T1, regulator T2, capacitor, reactor, isolation valve and switch; capacitors include successively parallel connecting capacitor C1, C2, C3, reactor is L, isolation valve include successively parallel connecting isolation valve V1, V2, V3, resistance is R, switches include successively parallel connecting switches S1, S2 and S3; The said isolation valves V1, V2 and V3, capacitors C1, C2 and C3, switches S1, S2 and S3 are series connecting reactor L successively; the said resistance R is series connecting switches S1, S2 and S3; the output of said direct current supply T1 connects resistance R; the said resistance R connects switches; the said switches S1, S2 and S3 separately connect isolation valve V1, V2, V3; the said regulator T2 parallel connects direct current supply T1.

In the second preferred embodiment of this invention, the direct current supply 2 of test apparatuses comprises huge current transformer T, breaker, isolation switch, limiting reactor, reactor Lh and L1, and 6 pulse bridge rectifier B6; the said huge current transformer T, breaker, isolation switch and limiting reactor successively series connect; the output of 6 pulse bridge rectifier B6 connects successively series connecting reactor Lh and L1.

In the third preferred embodiment of this invention, the said method comprises following steps:

A. the said direct current supply 2 working to make output current reach heating point, the switch of default current 4 closes for charging capacitors to make capacitor voltage reach test requirement;

B. closing the said auxiliary valve 3 to make direct current of direct current supply 2 flow into test valve 1, to heat test valve 1;

C. after the said test valve 1 being heated to certain temperature, opening isolation valve V1, V2 and V3 in default current supply 4 to make default current supply 4 flow default current to test valve 1, in order to create test valve 1 default voltage;

D. triggering the said impulse voltage generator 5 to make impulse voltage generator 5 providing test valve 1 with impulse voltage, to be mixed with default voltage of default current supply 4 to form voltage in test valve 1.

In the fourth preferred embodiment of this invention, in the said step A, during single wave default current test, switch S1 in default current supply 4 closing for charging capacitor C1, to make voltage of capacitor C1 reach test requirement; during triple wave default current test, switches S1, S2 and S3 of default current supply 4 separately charge capacitors C1, C2 and C3, to make voltages of capacitors C1, C2 and C3 reach test requirement.

In the fifth preferred embodiment of this invention, in the said step C, during single wave default current test, default current supply 4 providing test valve 1 with reverse voltage and partial forward voltage after default current; in the said step D, during single wave default current test, the said impulse voltage is forward impulse voltage, during triple wave default current test, the said impulse voltage is reverse impulse voltage being placed upon test valve 1 after second default current.

In the sixth preferred embodiment of this invention, the said method employs symmetrical positive and negative voltages to be mixed with impulse voltage to form asymmetrical forward and reverse voltages, to make test voltages reach exactly the climax upon specific timing.

This invention provides one default current test method of impulse voltage mixed high voltage direct current converter valve, its circuit is comparatively simpler without high voltages in normal default current tests, high voltages have been replaced by impulse generator employing positive and negative symmetrical voltages mixed with impulse voltages to form asymmetrical forward and reverse high voltages, meanwhile the timing for impulse voltage is flexible, the amplitudes could be continuously adjustable according to specific needs, to make test voltage exactly reach climax upon certain timing, the test is flexible and safe, to be applied to converter valves in different direct currents.

FIGURE DESCRIPTION

FIG. 1 shows the default current test apparatuses in the impulse voltage mixed high voltage direct current converter valve;

FIG. 2 shows following up blocking single wave default current test wave shape;

FIG. 3 shows non-following up blocking multiple wave default current test wave shape.

EMBODIMENTS

According to the Figures, detailed description of embodiments of this invention is as follows.

FIG. 1 shows the default current test apparatuses in the impulse voltage mixed high voltage direct current converter valve, the apparatuses comprise test valve 1, direct current supply 2, auxiliary valve 3, default current supply 4 and impulse generator 5. impulse generator 5 parallel connecting test valve 1 series connects auxiliary valve 3; test valve 1 series connecting auxiliary valve 3 forms the bridge of 6 pulse bridge rectifier B6 in direct current supply 2; inductance L in default current supply 4 parallel connects impulse generator 5.

During the test, direct current supply 2 provides test valve 1 with heating current before default current to make it reaches certain temperature, after heating current dies in test, auxiliary valve 3 isolates direct current supply 2; test valve 1 being heated to certain temperature, default current supply 4 provides test valve 1 with default current, during single wave default current test further to provide test valve 1 with reverse voltage and partial forward voltage after default current; impulse voltage generator 5 provides test valve 1 with impulse voltage, during triple wave default current test, the said impulse voltage is reverse impulse voltage being placed upon test valve 1 after second default current.

FIG. 2 shows following up blocking single wave default current test wave shape, during single wave default current test, the said impulse voltage is forward impulse voltage, to be mixed with forward voltage of default current supply 4 to form positive voltage of test valve 1, to suppress one hugest amplitude of single wave default current, beginning from highest temperature, reverse and forward voltages following blocking, including any over voltage due to load rejection.

Single wave default current test comprises following steps:

1) direct current supply 2 working to make output current reach heating point, the switch S1 of default current 4 closes for charging capacitors to make capacitor voltage reach test requirement;

2) closing the said auxiliary valve 3 to make direct current of direct current supply 2 flow into test valve 1, to pre-heat test valve 1;

3) after the said test valve 1 being heated to certain temperature, closing auxiliary valve 3, opening isolation valve V1 in default current supply 4 in order to create test valve 1 default current;

4) after default current dies, charging capacitor C1 voltage reverses to make test valve 1 bear reverse voltage;

5) recharge capacitor C1 to make its voltage reach the point before default current;

6) impulse voltage generator 5 triggers upon 5 ms after default current, to provide test valve 1 with forward impulse voltage.

FIG. 3 shows non-following up blocking multiple wave default current test wave shape, during triple wave default current test, impulse voltage is reverse voltage which will be placed upon test valve after the second default current. With the same conditions of single wave test, until breaker trips, multiple wave default current still exists, without any forward voltages.

Triple wave default current test comprises following steps:

1) direct current supply 2 working to make output current reach heating point, the switch S1 of default current 4 closes for charging capacitors to make capacitor voltage reach test requirement;

2) closing the said auxiliary valve 3 to make direct current of direct current supply 2 flow into test valve 1, to pre-heat test valve 1;

3) after the said test valve 1 being heated to certain temperature, closing auxiliary valve 3, opening isolation valve V1 in default current supply 4 in order to create test valve 1 the first default current;

4) open auxiliary valve V2 in default current supply 4 to create test valve 1 a second default current;

5) impulse voltage generator 5 triggers upon 5 ms after default current, to provide test valve 1 with reverse impulse voltage;

6) open auxiliary valve V3 in default current supply to create test valve 1 a third default current.

The test method of this invention is comparatively simpler without high voltages in normal default current tests, high voltages have been replaced by impulse generator employing positive and negative symmetrical voltages mixed with impulse voltages to form asymmetrical forward and reverse high voltages, meanwhile the timing for impulse voltage is flexible, the amplitudes could be continuously adjustable according to specific needs, to make test voltage exactly reach climax upon certain timing, the test is flexible and safe, to be applied to converter valves in different direct currents.

It is at last to be mentioned, above description of this invention with embodiments shall not be regarded as limitation to this invention. Those skilled in this art shall understand the embodiments of this invention could be modified or alternatively replaced, only these modification or replacement all fall into the claims of this invention. 

1. One default current test method of impulse voltage mixed high voltage direct current converter valve, the apparatuses in said method comprises test valve (1), direct current supply (2), auxiliary valve (3), default current supply (4), it characterized in that, the apparatuses in said method comprises impulse generator (5); the said impulse generator 5 series connects auxiliary valve (3) after parallel connecting test valve(1); the said test valve (1) series connects auxiliary valve (3) to form bridge of (6) pulse bridge rectifier B6; the inductance L of said default current supply (4) parallel connects impulse generator (5).
 2. The default current test method of impulse voltage mixed high voltage direct current converter valve in claim 1, the default current supply (4) of test apparatuses comprise direct current supply T1, regulator T2, capacitor, reactor, isolation valve and switch; capacitors include successively parallel connecting capacitor C1, C2, C3, reactor is L, isolation valves include successively parallel connecting isolation valve V1, V2, V3, resistance is R, switches include successively parallel connecting switches S1, S2 and S3; The said isolation valves V1, V2 and V3, capacitors C1, C2 and C3, switches S1, S2 and S3 series connect reactor L successively; the said resistance R series connects switches S1, S2 and S3; the output of said direct current supply T1 connects resistance R; the said resistance R connects switches; the said switches S1. S2 and S3 separately connect isolation valve V1, V2, V3; the said regulator T2 parallel connects direct current supply T1.
 3. The default current test method of impulse voltage mixed high voltage direct current converter valve in claim 1, the direct current supply (2) of test apparatuses comprises huge current transformer T, breaker, isolation switch, limiting reactor, reactor Lh and L1, and 6 pulse bridge rectifier B6; the said huge current transformer T, breaker, isolation switch and limiting reactor successively series connect; the output of 6 pulse bridge rectifier B6 connects successively series connect reactor Lh and L1.
 4. The default current test method of impulse voltage mixed high voltage direct current converter valve in claim 1, the said method comprises following steps: A. the said direct current supply (2) working to make output current reach heating point, the switch of default current (4) closing for charging capacitors to make capacitor voltage reach test requirement; B. closing the said auxiliary valve (3) to make direct current of direct current supply (2) flow into test valve (1), to heat test valve (1); C. after the said test valve (1) being heated to certain temperature, opening isolation valve V1, V2 and V3 in default current supply (4) to make default current supply (4) flow default current to test valve (1), in order to create test valve (1) default voltage; D. triggering the said impulse voltage generator (5) to make impulse voltage generator (5) provide test valve (1) with impulse voltage, to be mixed with default voltage of default current supply (4) to form voltage in test valve (1).
 5. The default current test method of impulse voltage mixed high voltage direct current converter valve in claim 1, in the said step A, during single wave default current test, switch S1 in default current supply (4) closing for charging capacitor C1, to make voltage of capacitor C1 reach test requirement; during triple wave default current test, switches S1, S2 and S3 of default current supply (4) separately charge capacitors C1, C2 and C3, to make voltages of capacitors C1, C2 and C3 reach test requirement.
 6. The default current test method of impulse voltage mixed high voltage direct current converter valve in claim 1, in the said step C, during single wave default current test, default current supply 4 providing test valve 1 with reverse voltage and partial forward voltage after default current; in the said step D, during single wave default current test, the said impulse voltage is forward impulse voltage, during triple wave default current test, the said impulse voltage is reverse impulse voltage being placed upon test valve (1) after second default current.
 7. The default current test method of impulse voltage mixed high voltage direct current converter valve in claim 1, the said method employs symmetrical positive and negative voltages to be mixed with impulse voltage to form asymmetrical forward and reverse voltages, to make test voltages reach exactly the climax upon specific timing. 